This invention relates to a medical treatment, and particularly to a blood dialysis. Furthermore, it relates to an apparatus for charging blood into a blood dialyzer, and a method for charging blood therein.
In general, blood is most easily coagulated at a blood inlet portion and a blood outlet portion (header) of a hollow yarn type blood dialyzer. Therefore, various proposals have heretofore been made in order to solve this problem, as discussed, for example, in Japanese Patent No. 1267833, Japanese Patent Publication No. Sho 62-54510, and Japanese Laid-Open (Kokai) Utility Model Application No. Sho 63-100051. In these publications, it is proposed to improve the configuration of a header portion in order to prevent blood from being coagulated at the header portion.
In an actual blood dialyzing operation, a flow rate of blood flowing in the blood dialyzer can range widely from 100 to 300 ml per minute, and in addition, consistency of blood differs for each individual patient.
On the other hand, this consistency of blood varies with the passage of time during the dialyzing operation. Therefore, a simple modification made to the configuration of the header portion is not enough to cope with all requirements under different conditions.
It is known that blood is readily coagulated when it contacts foreign matter outside the body. Particularly, when the flow of blood is slowed down or stagnated, the blood begins to coagulate at that spot.
In the case where blood is circulated outside of the body during a blood dialyzing operation, blood is most easily coagulated at a header portion h of a blood dialyzer shown in FIG. 2, because the blood coming from a blood circuit 1 is charged into the wide header portion h having an inner diameter of 40 to 50mm through a narrow inlet port i having an inner diameter of 3 to 4mm, and the blood flow is suddenly slowed down.
Specifically, the blood flowing through a central portion of the header h flows fast linearly from the inlet port. However, since the blood flow is stagnated at an area near the circumference of the header h, the blood begins to coagulate in a ring pattern first from the area near the circumference of the header, and then the blood coagulation is gradually spread towards the center of the header h.
When the blood coagulation is further spread to block an inlet of a dialyzing film of the hollow yarn, the blood in the hollow yarn is stopped from flowing and therefore becomes coagulated. In order to circulate the blood safely outside of the body without coagulation, a blood anti-coagulation agent is used. However, this chemical agent is sometimes accompanied by a side reaction. Particularly, if this is used for a patient suffering from a hemorrhagic concurrent disease or a patient before or after an operation, there is a risk of bleeding, and therefore the amount of use of the anti-coagulation agent must be reduced as much as possible.